Hey guys. My iPhone 4 recently broke and I've been using an old Bold 9700 for a couple weeks. I wanted to upgrade to the 9900 for the last 10 months of my contract before considering hardware upgrades available then.

I'm looking on kijiji and found a few in the price range I'm looking for. I'm just wondering what are some basic things that I should look for or test before agreeing to buy? I'm going to bring my SIM card, so obviously test to see if it connects to my network etc. What else should I do? Is there any way I can test for water damage? Is there anything that is worth testing in terms of software or is physical damage the only real risk? Anything else to consider before agreeing to the sale?